Production of phenols from redwood



W. I. HUND.

PRODUCTION 0F PHENOLS FROM REDWOOD1 APPLICATION FILED APR. 25,19I7-Patnted Jan. 11, 1921.

3 SHEETS-SHEET I.

.NANDN WlTN ESSES:

W. J.- HUND.

PRODUCTION 0F PHENOLS FROM REDWOOD.

APPLICATION man APR.25,19|1.

Patenwd Jan. 11, 1921.

3 SHEETS-SHEET 2- W. J. HUND.

PRODUCTION 0F PHENOLS FROM REDWOOD.

APPLlcAloN mao APR. 25. 1911.

1,365,407, Patented Jan. 11, 1921.

3 SHEETS-SHEET 3.

VITNESSES: 1 IN VENTOR ATTORNEYS UNITED .STATESI PATENT OFFICE.

WALTER J. HUND, or Ross, CALIFORNIA.

specmcation if Letterslra'tzeim VPatented J an. 11, 1921.

Application led April 25, 1917. Serial N 0. 164,438.

The principal sources of natural phenol are .coalland wood tars. Acoaltar is typified by a large proportion of phenol and the \threecresols. A wood tary is typified by large proportions'of guaiacol andcreosol. Coal tar yields from 8 to 25 per centfof the so-called middleoil, of which from 30 to 55 percent. is naphthalene. The rest isprincipally carbolic acid .and the cresols, with soine indifferent oils,the carbolic acid occurring to the extent of from 3 to 15 vper cent. ofthe middle oil, or from 0.3 to 3.0l

per cent., of the coal tar.l

In reference to the recovery of refined phenols from coal ,tar sources,it may be statedthat a considerable complication to the processes .isthe removal of thenapthalene. Not only vdo the middle oils have to bepressed to free them from the greater part of naphthalene content, butin-order to obtain a final crystalline phenol free from naphthalene, theoil must be treated chemically before fractionation, and further afterfractionation, in addition to several redistillat-ions.

Wood tars may, be roughly divided into two types, namely, resinous -woodtars and hardwood tars. Hardwoods are .distilled for oxyg'enatedproducts in preference to soft woods, because they give larger yields ofthese bodies, including phenols. About 20 per cent.`,of hardwood tar isphenolic, of

which on the averagef per cent. is guaiacol and creosol, 25 per cent.carbolic ,acid and cresols, or, in other words, 13 and 5v per cent.,respectively, ofthe tar. f

Tars from resinous woods distilled commercially, though the yieldof taras'such is greater than from hardwoods, contain a much smallerproportion of phenolic bodies. Thus while there might be a considerableyield of middle oil, only a small portion is phenolic and. soluble inalkali,

Redwood has no indication of being a wood suitable for destructivedistillation for the reason that it is a soft wood and a resinous wood,and the only resinous woods heretofore valuable for distillationpurposes were those rich in turpentine, which is practically absent inredwood. However, I have found as a result of many experiments thatwhenr the resin of redwood is subjected to destructive distillation in amanner similar to that practised with hardwood it produces a tar whichcontains large proportions of phenol and the three cresols still havingconsiderable proportions of guaiacol and creosol. It is a naturalintermediate between a coal tar creosote .and a woodtar creosote, withthe advantage over the former in that it has no `naphthalene or coal tarodor and the advantage over the latter in that it contains largeproportions of valuable and easily'isolated vlow-boiling phenols. Therelative proportions of the individual phenolsderived from redwood tarare different radically from the proportions of the individual phenolsmaking up any other natural combination from any of the other vknowntars from any source whatsoever.

The resin of the redwood is capable of producing commercially a highergrade of natural crystalline carbolic acid or cresylic acid than isobtainable froni any other known natural source. The carbolic acid andcresylic acid from this source are not contaminated with naphthalene orsulfur compounds and possess a distinct and different odor from thoseproduced from coal tars.

,Redwood, or Sequoia semperoirens, or coast redwood is a Conifer, of theAbietz'ne or Pinace, sub. Tawaene, a soft or resinous wood, of which anextensive use is made as atimber wood. Its needles, etc., containvolatile oil, the nature of which has been recorded in the case of theclosely related Sequoia gjgantea, the name sequojene hav- 'ing beengiven to a solid hydrocarbon typl# cal to the oil. The roots of bothsequoias are highly resinous in character, and those `can be attributedto the fact that hardwoods have been distilledA for the production ofalcohol, acetone and acetates, of which products hardwoods give amaximum yield; and

l light.

that resinous woods have been distilledfor their yield of turpentine androsin oils.

Ordinary rosin, or colophony, or the resins of the pines, upondestructive distillation will yield only traces of' phenolic bodies. Theresin of redwood, on the other hand, will yield alarge proportion ofdecomposition products of a phenolic character. bax'nples of redwoodresin distilled will yield oils, a large proportion of which is phenoliccon taining among other phenoloids catechol and homocatechol. Redwoodresin extracted from lightwood is brownish black in color, its powder alight brown reddish gray. It

is translucent in thin flakes and shows a' yields about to 45 per cent.of middle oil taken between 150 and 250 degrees, of which from 50 to 60per cent. is phenolic. The phenolic oils comprising from- 17.5 to 27.0per cent. of the tar will yield about 60 per cent. ofsphenols boilingbelow 200 and about 35 per cent. boiling between 200 and 220. Of the lowboiling phenols about 25 per cent. is crystallizable carbolic acid,which is about 15 per cent. of the total phenols, 7.5 to A8 vper cent.ofthe middle oil, 2.5 to 3.6 per cent. 'of the tar.

The tar contains no naphthalene, or at best only traces. It contains,likewise, only traces of sulfur compounds. By simple fractionaldistillation it is easily possible to obtain apcarbolic acid,crystalline and of ahigh degree of purity. The color of this crystallinecarbollc is a snow white, and does not change in the manner of phenolfrom coal tar sources. The coal tar odor is absent, and

the phenol has the more pleasinghardwood creosote odor.

The same applies to the cresols which can readily be isolated colorless,free from the usual coal tar odor, `with a hardwood creosote'odorinstead. About 35 per cent. of the phenol -from redwood tar consists ofthe cresols, or about 20 per cent. of the total phenols, 10 per cent. ofthe middle oil and 5 per cent. of the tar.

About 35 per cent. ofthe phenols are guaiacol and creosol, the latteroccurring i lthe larger proportion, which phenoloids occur to about thesame extent as the cresols.

In the accompanying drawings:

Figure 1 shows diagrammatically thefirst group of steps employed in myprocess.

Fig. 2 shows the second group.

Fig. 3 shows the third group.

The three groups areto be read in sequence.

In the drawings the unshaded rectangles indicate materials, apparatus'and process steps necessary for the production of phe-l nolic bodies inaccordance with the preferred form of my invention; the diagonallyshaded rectangles indicate materials, apparatus and process steps notnecessary but still advisable forrecovering the by-products; and thevertically shaded rectangles indicate commercially utilizable phenoloidbodies or products, the value of which is due to phenoloidcharacteristics.

I take alquantity of selected'wood obtained from the broken-up stumps ofSeguaio; semperorem or redwood, the selected wood being that which inthe case of resinous woods is known as light-wood, or wood rich inresins. A cord of this wood will weigh approximately 4,000 pounds. -Iprepare this wood in the following manner:

I season it well and cause it to dry, either in the air or in kilns, soas to allow the evaporation of most of the water it may contain.

When it has become as dry as is practicable,

I prepare it lfurther for the retort, in that .I'

saw, or chip,'shred or hog and compress the comminuted wood intobriquets, or in other ways physically treat lthe wood in order that itmay possess a definite degree of uniformity. It is desirable to reducethe wood to a definite degree of uniformity in order to allow a bettercontrol in the subsequent distillation of the prepared wood.

I next subject the prepared wood to destructive distillation. I pack thewood in a vessel of suitable construction in;which it may be subjectedto a temperature which may be in excess of 450 C., thereby causing it todecompose, from which vessel the volatile products may issue freely toand through a condensing system wherein thatk portion of the condensateoily in character and known as tar is gathered and separated from otherdecomposition products. I can accomplish the production of the tar withany tarproduction and recovery process used in the retort, oven or kilnsys# tems of hardwood distillation.

In this way I obtain from each cord of wood 50 to 60 gallons of tar witha speciiic gravity of about 1.11. This tar further has approximately theusual physical characteristics of a woodtar. p

I then distil the oils of the tar from its pitchmaking use of anysuitable tar still, and condense and collect separately the oilsdisti1ling[ over between 150 and 250 centigrade. call this oil themiddle oil from redwood tar and obtain from 20 to 25 gal- -lons of it.It has an empyreumatic odor like similar fractions obtainable fromhardwoodl tars, and though it may at first have a pale or dark yellowamber color, it rapidly darkens to a dark reddish brown soon afterdistillation.

I next determine the amount of' alkalisoluble material of' the middleoil. by taking 10 cubic centimeters of the oil in a graduated tube, andadd gradually four .or five times as much, or 40 to 50 `cubiccentimeters of a 10 per cent. solution of sodium hydroxid. I then closethe tube and agitate it well, whereupon the alkali-soluble material willbe completely dissolved by the alkaline liquid. Upon standing theinsoluble oils will gather in a separatestratum. When the separation ofthe alkaline liquid and the undissolved oil is complete', I read thevolume of the undissolved oil, and sub- -tract this volume from l0 cubiccentimeters,

and the figure obtained represents the volume of alkali soluble materialin each ten cubic centimeters of the middle oil. Knowing the volume ofalkali soluble material in the oil, I calculate the minimum amount of aknown solution of an. alkaline hydrate necessar -to dissolve thealkali-soluble material o the middle oil.

I then place the middle oil in a suitable vessel, wherein it is agitatedwith the calculated amount of the warm solution of an alkaline hydrate,until solution is complete. The solution of an alkaline hydrate shouldapproximate a strength of from 6 to 10 per cent. sodi m hydrate, or aspecific gravity of' from l. 0 to 1.15. When the liquids have been'thoroughly mixed and agitated and the soluble oils have gone intosolution, I draw off the undissolved oils and treat the alkalineliquorwith a slight excess of a dilute acid solution, for instance a solutionof sulfuric acid, corresponding to about 12 per cent. acid. The quantityof acid added can be vcalculated or neutralization may be judged byobvious color changes in the treated liquor. This acid treatment of thealkaline-liquor will liberate the dissolved oils, which are thenwithdrawn andwashed with water enough to remove the excess of acid ifanyi's present. In thisway I obtain from 10 to 15 gallons of an oilentirely.'

phenolic in character, which contains various phenols in differentproportions than any total phenolic oil from any other known tar. Todistinguish this redwood phenolic oil from other ,phenolic tar oils Icall it sequojol, raw. f

I then subject'the redwood phenolicxoilv to distillation, either direct,in which case I collect the portion distilling over between 17 0 and-230centigrade, or with steam, in

I do this which case collect the total oils of the condensate separatingout upon saturating the aqueous portion oi the distillate withaw'ater-soluble salt, such as sodium chlorid, calcium chlorid, sodiumsulfate.

By subjecting this redwood phenolic oil still in its raw state tofractional distillation ,from a still of the type of the socalled phenolstill, I obtain precisely the following percentages of phenols Table 1'.

From 178 to 186 degrees C 25 per cent. carbolic oil From 186 to 195degrees C. 10 per eent.}c es lic i, groin Eo 03 gegrees 2g per cenit. ry o rom o 1 egrees ercen. From 210 to 220 degrees C 14 iiercentlcleosote on Table II.

From 17s to 18e degrees c so pei cent. carbone on From 1,86 to 195degrees Cllll-.lllllllllll 13 per cent. From 195 to 203 degrees C. 25per centlmresyhc o From 203 to 210 degrees C. 9 per cent. creosote ouFrom 210 to 220 degrees C f 17'per cent.

The higher percentages of recoveries by the last-described methodillustrated in Fig. 2, is due simply to the comparative. crudeness ofthat process as against the first-described process Fig. 3, where therefinement and separation is final and complete.

It is not to be understood that the two more or less suggested by thenature of the derived products.

The first of the above-named fractionsin Table Lto-wit: carbolic oil,when subjected to a. low temperature, say 0 degrees centigrade, 'willsolidify 'and is 80 er cent. or more-crystallizable phenol. drain thecrystallized phenol from its unsolidied oils, by means of 'a centrifugalmachine, or other suitable means; the crystals so obtained are carbolicacid crystals. The oil drained from the crystals I add to the vvcombined fractions 186-195 and 195- 203", and the resulting oiliscresylic acid. The combined fractions 20W-210o 210-220 constitutecreosote.

and-

The three last named phenolic products I l obtain in the followingamounts:

Cai-bolle acid crystalline. 17 to 20 lbs. Cresylic acid 4 to 5 gallonsCreosote 2 to Sgallons "This natural combination of' phenols con;

stitutes a commercial source of higher grade natural crystallinecarbolic acid 01j cresylic creosote odor in its stead. No specialtreat-A ment of the carbolic acid is necessary to eliminate colorationpropensities, inasmuch as the acid from this source will not readilydiscolor.

By using redwood tar instead of coal tar as a source for this purpose, Ifind that I can eliminate several of the purication processes nownecessary and hitherto thought necessary in carbolic acid isolation fromnatural sources.

Having thus described my invention, what I claim and desire to secure byLetters Patent is-- l. The process of producing phenoloid bodies fromredwood, which comprises heating comminuted resinous redwood in a retortat a temperature above 450C., collecting the tar formed by such heating,fractioning out of the tar an oily distillate between 150 and 250 C.,treating said oily distillate with caustic alkali solution whereby aportion thereof is dissolved, separating the mixed phenolic substancesfrom the solution so formed and separating the phenolic compounds. v2.The production of phenolic oil from resinous redwood, which includesdestructive distillation of the raw wood at temperatures exceeding 450C., and subjecting the resulting raw redwood phenolic oil to fractionaldistillation to segregate the derived phenols.

3. The production of a new natural combination of valuable phenols whichconsists in the destructive distillation of the resin of redwood,without previously isolating the same from the wood, this destructivedistillation being carried on at a temperaturein C to agitation with hotcaustic alkali solution, drawing off the residual oils and treat.

ing the alkaline liquor with a slight excess of a dilute acidsolution'toliberate the dissolved oils and then withdrawing and washing said oils,the resulting product being a raw redwood phenolicv oil.

4. The process of producing phenolic -6. The process of producingphenoloid Ybodies from redwood which consistsin treating suitablycomminuted resinous redwood in a retort at a temperature exceeding 450C. to recover raw tar, fractioning out from the tar the middle oil at'atemperature of 150 to 250 C., treating this middle oil with causticalkali solution whereby some ofthe middle oil dissolves and separatingthe dissolved oil from the solution so formed.

7. In the process of obtaining phenolic compounds from redwood, thestepsl of destructively distilling the redwood at a temperaturenot muchabove 450 C., and col` lecting the tar so formed.

8. In the process of obtaining phenolic compounds from the wood ofSeguo'iaseynperm're'ns, the steps of destructively distillingv the woodata temperature not much labove 450 C., collecting the tar so formed,distilling said tar and, collecting the fraction containing the bulk ofthe phenolic compounds.

9. The cresote oilof redwood tar, which comprises the distillate ofredwood tar recovered between 4the limits 150 to 250 deg. C., and whichcontains approximately per cent. of phenols. d

10. Redwood tar, consisting of the tar obtained by destructivelydistilling the ifwood of the Sequoia semperoirem, which tar containsapproximately 30 per cent. of phenols.

11. The phenol of redwood tar whlch 1 s obtained from redwood tar as setforth 1n claim'lO, and which has In testimony whereof I have hereuntoset my hand in the presence of two subscribing witnesses.

f WALTER J. HUND.

Witnesses;

IJOHN H-.HnRRING,

W. HEALEY.

the approximate compounds, which comprises destructively

